A microtome has been widely known as a device for preparing a sliced specimen used for physical and chemical specimen analysis, microscopic observation of biological specimens, and the like. The microtome slices a surface of a specimen block, which is obtained by embedding a biological specimen or the like in an embedding-substance such as paraffin, with a cutter to prepare a slice.
The slice prepared by use of the microtome is, for example, collected in a bath filled with a extending liquid such as water or hot water with a blush or paper to be extended out and then, is stuck to a slide glass with an adhesive liquid (for example, water). Alternatively, the slice is placed directly on the slide glass to which an adhesive is applied, and is extended out by heating of the slide glass and is stuck to the slide glass. With evaporation of the adhesive liquid, the slice stuck to the slide glass is tightly fixed to the slide glass, and is used as a sliced specimen for tissue observation.
When the surface of the specimen block is sliced to form the slice, for effective tissue observation, a specimen portion needs to be sufficiently present on the surface of the specimen block from which the slice is cut out. Thus, generally, the specimen block is roughly cut by a predetermined thickness and then, is sliced for acquiring the slice for tissue observation. Roughly cutting the surface of the specimen block before slicing for tissue observation is referred to as surface exposure.
To resolve inclination of the surface of the specimen block with respect to a cutting surface of a cutter, there have proposed a method and a device that use a floodlight projection part and line sensor, which are arranged along the thickness of the specimen block, and incline the surface of the specimen block such that the amount of light that the line sensor receives becomes maximum, and perform surface exposure of the specimen block at this position as described in Japanese Patent Laid-open Publication No. 2008-76251. The surface exposure in this case serves to match the inclination angle of the surface of the specimen block with the cutting surface of the cutter, and is the same as the surface exposure in this application in a broad sense: “to acquire the surface for slicing for tissue observation”, but is different from the surface exposure in this application in a narrow sense: “to acquire the surface for effective tissue observation”.